Comment 3 for bug 1630387

Just chiming in here, this is indeed a requirement for actual usability of the charm to configure SR-IOV functionality

Hardware:
04:00.0 Ethernet controller [0200]: Intel Corporation Ethernet Controller 10-Gigabit X540-AT2 [8086:1528] (rev 01)
04:00.1 Ethernet controller [0200]: Intel Corporation Ethernet Controller 10-Gigabit X540-AT2 [8086:1528] (rev 01)

Log of failed usage AS-IS:
2017-05-31 11:09:51.015 70030 DEBUG neutron.plugins.ml2.drivers.mech_agent [req-17f2509f-e688-4052-aee2-a9f2965a44b9 158ef64791b2439784e9cfa6077a382f 148d0a576d394bf6947d1d3578b87eda - - -] Attempting to bind port 86afc89d-78ac-464b-bbc3-9b48e84da140 on network 90b95619-a4d4-4ef5-9134-50ae9c3139c5 bind_port /usr/lib/python2.7/dist-packages/neutron/plugins/ml2/drivers/mech_agent.py:60
2017-05-31 11:09:51.015 70030 DEBUG neutron.plugins.ml2.drivers.mech_agent [req-17f2509f-e688-4052-aee2-a9f2965a44b9 158ef64791b2439784e9cfa6077a382f 148d0a576d394bf6947d1d3578b87eda - - -] Refusing to bind due to unsupported vnic_type: direct bind_port /usr/lib/python2.7/dist-packages/neutron/plugins/ml2/drivers/mech_agent.py:65
2017-05-31 11:09:51.016 70030 DEBUG neutron.plugins.ml2.drivers.mech_sriov.mech_driver.mech_driver [req-17f2509f-e688-4052-aee2-a9f2965a44b9 158ef64791b2439784e9cfa6077a382f 148d0a576d394bf6947d1d3578b87eda - - -] Attempting to bind port 86afc89d-78ac-464b-bbc3-9b48e84da140 on network 90b95619-a4d4-4ef5-9134-50ae9c3139c5 bind_port /usr/lib/python2.7/dist-packages/neutron/plugins/ml2/drivers/mech_sriov/mech_driver/mech_driver.py:98
2017-05-31 11:09:51.016 70030 DEBUG neutron.plugins.ml2.drivers.mech_sriov.mech_driver.mech_driver [req-17f2509f-e688-4052-aee2-a9f2965a44b9 158ef64791b2439784e9cfa6077a382f 148d0a576d394bf6947d1d3578b87eda - - -] Unsupported pci_vendor 8086:1515 _check_supported_pci_vendor_device /usr/lib/python2.7/dist-packages/neutron/plugins/ml2/drivers/mech_sriov/mech_driver/mech_driver.py:179
2017-05-31 11:09:51.017 70030 DEBUG neutron.plugins.ml2.drivers.mech_sriov.mech_driver.mech_driver [req-17f2509f-e688-4052-aee2-a9f2965a44b9 158ef64791b2439784e9cfa6077a382f 148d0a576d394bf6947d1d3578b87eda - - -] Refusing to bind due to unsupported pci_vendor device bind_port /usr/lib/python2.7/dist-packages/neutron/plugins/ml2/drivers/mech_sriov/mech_driver/mech_driver.py:110

Manual resolution / workaround:
- Add 'supported_pci_vendor_devs = 8086:1515' to /etc/neutron/plugins/ml2/ml2_conf_sriov.ini on neutron-api units
- Extend NEUTRON_PLUGIN_CONFIG in /etc/default/neutron-server with: ' --config-file=/etc/neutron/plugins/ml2/ml2_conf_sriov.ini' on neutron-api units